var txt = document.getElementById('txt');
            var start = document.getElementById('start');
            var end = document.getElementById('end');
            var person = ['阿毛','阿财','阿狗'];
            var time;
            start.onclick=function(){
                clearInterval(time);
                time=setInterval(function(){
                    var num = parseInt(Math.random()*person.length);
                    txt.innerHTML=person[num];
                },100)
            }
            end.onclick=function(){
                clearInterval(time);
            }